Electronic confinement at nanoscale dimensions remains a central means of science and technology. I will describe a novel method for producing electronic nanostructures at the interface between two normally insulating oxides, LaAlO3 and SrTiO3. Conducting nanostructures are written, erased and reconfigured under ambient conditions at room temperature, similar to the operation of an etch-a-sketch toy. A wide variety of devices can be created, including nanowires, tunnel junctions, diodes, field-effect transistors, single-electron transistors, superconducting nanowires, and nanoscale THz emitters and detectors. After an introduction, I will focus on two recent results: the discovery of a novel phase in which electrons form pairs without becoming superconducting, and the discovery of electronically controlled ferromagnetism at room temperature. Both phenomena occur in the same family of LaAlO3/SrTiO3 heterointerfaces.
